The present invention generally relates to saw blades of the kind used for sawing hard and/or abrasive materials such as granite, marble, concrete, asphalt and the like. More particularly, the present invention relates to saw blade cutting segments containing thermally stable, polycrystalline diamond abrasive grit as the cutting elements.
Conventionally, the cutting of hard materials such as granite, marble, filled concrete, asphalt and the like is achieved with the use of diamond saws. The blade of a saw of this type comprises a circular steel disc having a plurality of segments spaced consists essentially of diamond abrasive bonded in a suitable alloy or metal matrix, such as bronze or cobalt, for example. The diamond abrasive typically is either a single crystal natural diamond or a single crystal synthetic diamond.
Such prior art saw blades suffer from several disadvantages, including the tendency of such single crystal diamonds to wear smooth or to fracture completely through the crystal during use. It is possible to control these shortcomings to a certain extent by proper selection of the bond matrix and blade operation conditions, particularly surface speed of the saw blade. Another approach to avoiding these disadvantages is through the design of the saw blade and/or the saw blade segment.
More recently, U.S. Pat. No. 4,776,861, assigned to the same assignee of the present invention, suggested that thermally stable polycrystalline diamond abrasive grit could be utilized in the manufacture of saws, however, this patent gives no guidance as to how such diamond grit should be incorporated into the saw blade segments. Furthermore, there is no teaching or suggestions that any advantage can be obtained over prior art saw blades using single crystal diamonds by employing thermally stable polycrystalline diamond abrasive grit.